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High Power Density Asymmetrical Full-Bridge Soft-Switching Inverter
Pei-Chin Chi,Cheng-Yen Chou,Marojahan Tampubolon,Yao-Ching Hsieh,Jing-Yuan Lin,Huang-Jen Chiu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
This paper presents a Zero-Voltage-Switching (ZVS) technique eliminating the switching loss on a proposed single phase bi-directional full-bridge Buck inverter in which asymmetrical filter topology and control scheme are for each arm. Here Metal-Oxide-Field-Effect- Transistor(MOSFET) is chosen as the switching device, an L₁-C₁ filter is connected across the full-bridge, an L₂ filter is connected in series to load or grid. While the arm connecting with the C₁ is controlled by the polarity of 50Hz sinusoid reference command and the arm connecting with the L₁ is controlled by a Pulse-Width-Modulation(PWM) signal modulated by sinusoid, the L₁-C₁ then operates as an output filter of Buck, and the succeeding L₂ filter further attenuates ripple current flowing to load or grid. The ZVS technique sets the L₁ inductance such low that its current flows bi-directionally within a switching period, then the bidirectional current with sufficiently high peaks in turn charge and discharge the output capacitance Coss of MOSFETs of the switching arm within floating time, defined as the duration when both MOSFETs of an arm are off, to let the MOSFETs D-S channels be turned on or off at the state that Coss are fully discharged to zero voltage, so ZVS of MOSFET is achieved. Under the ZVS operation without frequency proportional switching loss, the switching frequency is possible to be raised to high to compact the sizes of passive components and heat sink of the inverter for achieving high power density. Simulation and experiment have been carried out to verify the ZVS operation.
Wen-Jie Zou,Chin-Wei Huang,Yung-Ho Chiu,Neng Shen,Shu-Mei Wang 기술경영경제학회 2016 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.24 No.3
This study uses the dynamic data envelopment analysis (DEA) model to evaluate intertemporalefficiency for high-tech industries in China. The significant difference from previous studies isthe assumption for patents, which are defined to be a carry-over intermediate linking differentterms. The model further provides an indicator of adjustment ratio for patents, based on theassessment of optimal quantity of patents. Output and input inefficiency indicators are alsodeveloped in the model to explore the sources of operational inefficiency. The empiricalresults conclude that intertemporal efficiency trends upward over time; the quantity ofpatents is assessed to be in shortage during the early terms, but excessive in recent terms;and that deficits in financial output is a significant factor in creating inefficiency.
A DSP-Based Differential Boost Inverter with Maximum Power Point Tracking
Marojahan Tampubolon,Irwan Purnama,Pei-Chin Chi,Jing-Yuan Lin,Yao-Ching Hsieh,Huang-Jen Chiu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
This paper presents a DSP-based differential boost inverter (DBI) with maximum power point tracking (MPPT) for photovoltaic (PV) applications. In a conventional DC/AC MPPT system, power of photovoltaic is delivered into two stages, they are DC/DC boost converter and buck type DC/AC inverter. A DC link capacitor appears between these two stages. Furthermore the system has higher complexity and costly than that of DC/AC MPPT system with a single stage boost inverter. Here, a single stage differential boost inverter is implemented. Since it can produce a sinusoidal output voltage higher than its DC voltage input, it is not only able to reduce the stage number of DC/AC MPPT system but also able to eliminate the DC link capacitor. The MPPT method employed in this study is P&O method. This technique is widely used due to its easy implementation, and unimportant extreme weather change consideration. To implement this technique, a digital signal processor (DSP) was used. In this paper, a review of DBI and MPPT implementation are presented. Finally a 400W laboratory prototype has been built. The result shows that the P&O MPPT method has been successfully implemented for various PV power and it can reach 95% maximum MPPT accuracy. In addition, the DBI is able to produce a sinusoidal output voltage at the various PV power conditions.